To determine the incorrect statement regarding cellulose from the given options, let's analyze each one: Option A: "It does not reduce Fehling's solution nor Tollen's reagent." This statement is correct. Cellulose is a polysaccharide and does not have free aldehyde or ketone groups needed to act as a reducing sugar. Therefore, cellulose does not react with Fehling's solution or Tollen's reagent, both of which test for the presence of reducing sugars. Option B: "On heating with dil. H2SO4 under pressure, cellulose gets hydrolysed to D-Glucose." This statement is correct. When cellulose is treated with dilute sulfuric acid under pressure, it undergoes hydrolysis to produce D-glucose. This is a typical behavior of cellulose undergoing acidic hydrolysis. Option C: "It is a straight chain polysaccharide made of β− D-glucose units." This statement is correct. Cellulose is a linear, straight-chain polysaccharide consisting of β - D-glucose units. These glucose molecules are linked by β-1,4-glycosidic bonds, contributing to the rigid structure of cellulose. Option D: "The β-glycosidic linkages are between C1 of one glucose unit and C5 of the next glucose unit." This statement is incorrect. In cellulose, the β-glycosidic linkages are indeed between the β forms of glucose, but they occur between the C1 carbon of one glucose molecule and the C4 carbon of the adjacent glucose molecule, not C5. This β−1,4-glycosidic bond is crucial for the linear structure of cellulose. Therefore, the incorrect statement regarding cellulose is Option D.